Anisotropic Conductive Elastomer (ACE) is a composite of conductive metal elements in an elastomeric matrix that is normally constructed such that it conducts along one axis only. In general this type of material is made to conduct through the thickness. In one reduction to practice, ACE achieves its anisotropic conductivity by mixing magnetic particles with a liquid resin, forming the mix into a continuous sheet and curing the sheet in the presence of a magnetic field. This results in the particles forming columns through the sheet thickness which are electrically conductive. The resulting structure has the unique property of being flexible and anisotropically conductive. These properties provide for a useful interconnection medium.
In another reduction to practice, ACE may consist of a matrix phase of an electrically insulating rubber sheet having a specified hardness and a dispersed phase of a multiplicity of metallic fine wire segments embedded in the matrix. The multiplicity of fine wire segments are substantially in parallel each with the others, and extend in a specified direction and in a specified distribution density. Each of the ends of the wire segments are exposed on the surface of the matrix sheet of rubber.
ACE must be compressed between top and bottom conductors to provide the interconnection. This is normally done by compressing the system using a backing plate and spring arrangement. One example of such is shown in FIG. 1. This requires the use of boards that are designed to accommodate the backing plate and holes. This can result in a conflict with components mounted under the device and on the back of the board. In addition, the ACE may be attached to a frame, where the frame extends horizontally beyond the dimensions of the adaptor board. This configuration may prevent the frame from interfering with the compressive force applied to the ACE, but may also result in a longer profile for the connector, thus restricting access to the substrate. In some applications, however, size limitations may prohibit the use of a frame.